laughable is not the right word. It - Aspartame - is obviously not the main thing. If he is drinking Aspartame then I think he is eating a lot of other stupid things as well.
but I think there is a case with Aspartame as shown in these few posts.
your comment on healthy people getting sick. It could be that the environmnet has caught up to them. Who would think that newspaper ink toxic that we breathe in everyday in our life.